When installing a door or window frame to an existing masonry opening, masonry anchors are frequently used to brace the frame against deformation. Certain conventional masonry anchors are provided as two-piece anchors including a flat rectangular plate and a U-shaped brace such as, for example, as illustrated in FIG. 7. Such anchors suffer from a variety of drawbacks and limitations, including those related to ease of installation and incompatibility with frames of different sizes. For these reasons among others, there remains a need for further improvements in this technological field.